Ein Endemit Zyperns:Asperula cypria (Rubiaceae) und seine Verwandtschaft

Galium suberosum Sibth. etSm. belongs toAsperula sect.Thliphthisa; the taxonomic transfer and a new name are therefore necessary:Asperula cypria Ehrend. is endemic on the isle of Cyprus. Its closest affinities are withA. antalyensis Ehrend. in S.W. Anatolia.

     

Revision der GattungLoxonia (Gesneriaceae)

Within the genusLoxonia Jack, currently regarded as monotypic, three species are recognized:L. hirsuta Jack (Sumatra, Mentawai-Islands, Java, Borneo, Anambas-Islands, Malay Peninsula),L. discolor Jack (Sumatra) andL. burttiana A. Weber, spec. nova (Borneo). [Key with English translation p. 203.] There is evidence thatL. discolor is the most primitive species within the genus, the two others being derived from it.

Teil V der Beiträge zur Morphologie und Systematik derKlugieae undLoxonieae (Gesneriaceae).     

Identification and restriction endonuclease mapping of the threonine operon regulatory region.

A DNA fragment carrying the thrP region of Escherichia coli has been identified and characterized. Starting from a secondary site lysogen of bacteriophage λ, where the position of the prophage is either within thrP or between thrP and thrP structural genes (Gardner et al., 1974; Gardner &; Smith, 1975) it has been possible to isolate transducing phages which carry bacterial DNA from either side of the prophage. By Int-Xis mediated site-specific recombination we have generated recombinant transducing phages which carry an intact thrP region. A phage carrying a regulatory mutation, which maps in the thrP region, has also been constructed.Mapping with several restriction endonucleases has allowed us to construct a map of the cleavage sites of the thrP region. A 1700 base-pair HaeIII fragment carrying the secondary attachment site (attΔOΔ′) was isolated and its position was localized within a 180 base-pair TaqI-HhaI restriction fragment. The location of attΔOΔ′ in the HaeIII fragment suggests that the entire thrP region is carried by this fragment.     

BENTHIC MARINE DIATOM ASSOCIATIONS: UPPER FLORIDA BAY (FLORIDA) AND ASSOCIATED SOUNDS1

Models of the diatom associations found in upper Florida Bay and adjoining sounds have been constructed utilizing Q modal factor-vector analysis and ecologic diversity indices (Shannon index, number of species, evenness). Four distinct associations were defined using Q-mode factor-vector analysis. Two associations were epiphytic, occurring on Thalassia testudinum König—Association I was characterized by Cocconeis placentula Ehr., Association III by Cylindrotheca closterium (Ehr.) Reim. & Lewin and Cocconeis placentula Ehr. The other two associations were epipelic, occurring on the carbonate mud substratum—Association II was characterized by Cyclotella striata (Kütz.) Grun., Rhopalodia gibberula (Ehr.) O. Müller and Surirella fastuosa (Ehr.) Kütz., Association IV by Fragilaria crotonensis Kitton and Cyclotella striata (Kütz.) Grun. The majority of the 161 species identified were present in both the epiphytic and epipelic assemblages. Only 33 species were restricted to the epiphyton, and 18 species restricted to the epipelon. The epipelic assemblage was significantly more diverse than was the epiphytic assemblage. A general trend of increased diversity away from terrestrial environs toward more open areas of water in both the epipelon and epiphyton was also found.     

STUDIES OF HAWAIIAN FRESHWATER AND SOIL ALGAE II. ALGAL COLONIZATION AND SUCCESSION ON A DATED VOLCANIC SUBSTRATE1,2

Spatial studies of colonization and succession of soil algae and chemical analyses of the various soils on the cinde cone of Kilauea Iki in Hawaii Volcanoes National Park, Hawaii are outlined. There is a positive correlation between the diversity and quantity of soil algae with nutrient levels and organic matter accumulation in each locale. Three distinct edaphic-biotic zones existing in this area are differentially revealed by the soil chemical composition, quantity and diversity of soil algae, and as evident variations in higher plant growth and colonization. Varying colonization and successional phases of higher plant growth around standing and fallen tree snags killed by volcanic activity also reflect variations in the soil algal flora. These variations appear largely as a function of differential water interception, absorption, and retention as well as differential accumulation of organic matter, and the initiation of various biogeochemical cycles.     

A serotonin sensitive guanylate cyclase associated with specific neurotransmitter binding sites on isolated synaptic membranes from mature rat brain.

Results from this study indicate that adult rat brain posesses guanylate cyclase activity sensitive to serotonin (5-HT) and localized in the synaptic plasma membrane. The enzyme appears to have multiple activation sites for 5-HT with specific activity maxima at the 5-HT concentrations of 5 × 10^?10M and 7 × 10^?8M respectively. The rates of guanosine-3′:5′-monophosphate (cyclic GMP) formation at these concentrations of 5-HT are, respectively, 170% and 307% above the endogenous or basal production rate of 2.7±0.3picomoles/minute/milligram of synaptosomal membrane protein. We have also been able to identify $\text{four}$ distinct types (Type #1, #2, #3, and #4) of high affinity, specific binding sites for 5-HT on isolated synaptosomal membranes from rat brain. Dissociation constants of 2.6 × 10^?10M, 2.5 × 10^?9M, 7.0 × 10^?9M, and 4.6 × 10^?8M, characterize the binding of 5-HT to our sites of Type #1 through Type #4 respectively. The specific, high affinity binding was saturated at 5-HT concentrations of 5 × 10^?10M for the Type #1 sites, 5 × 10^?9M for our Type #2 sites, 1 × 10^?8M for our Type #3 sites, and 7 × 10^?8M for our Type #4 sites. The 5-HT concentrations producing saturation of our specific binding sites of Type #1 and Type #4 are virtually identical to those that elicit the two maxima of 5-HT stimulated cyclic GMP production, indicating that a membrane-bound guanylase cyclase may be closely associated with certain 5-HT receptors and/or re-uptake sites.     

Plasma norepinephrine concentrations: No differences among normal volunteers and low,high or normal renin hypertensive patients

Plasma norepinephrine concentrations were measured by a sensitive radioenzymatic method in 51 patients with essential hypertension and 26 age-matched normal volunteers under conditions of ad libitum sodium intake, after volume expansion by infusion of saline intravenously, and after volume contraction by administration of furosemide orally. The hypertensive patients were classified into low, normal and high renin groups both by renin-sodium indexing and by their renin response to furosemide and saline administration. Plasma norepinephrine concentrations were similar among normal volunteers and patients with low, normal or high renin hypertension while the people were either recumbent or after they stood for 5 min. These and other results do not support the hypothesis that abnormal activity of the sympathetic nervous system accounts for the low or high renin values seen in many hypertensive patients.     

Composition of α-amylase secreted by aleurone layers of grains of himalaya barley

α-Amylases secreted by the aleurone layer of whole barley grains were relatively rich in histidine and relatively poor in glutamate/glutamine and serine when compared to other eukaryotic proteins. The secreted α-amylases had an estimated 0.5 residues each of glucose, mannose and N-acetylglucosamine per molecule of protein (MW 41 400 daltons), and gave positive staining reactions for carbohydrate on sodium dodecylsulfate polyacrylamide gels. Because the average α-amylase molecule had less than one sugar residue per enzyme molecule, it was concluded that secreted α-amylases were heterogeneous with respect to glycosylation. A second protein co-purified with α-amylase, but the amino acid composition of this protein was different from that of barley or wheat α-amylase. This protein was composed of two 21 500 dalton polypeptides. No significant amounts of L-leucine (¹⁴C-U) were incorporated into this second protein in isolated aleurone tissue during incubation with gibberellic acid, perhaps because much of it was already present in the starchy endosperm at the time of hormone addition.     

Polysaccharide component in the stigmatic exudate from Lilium longiflorum

The polysaccharide component of the stigmatic exudate from Lilium longiflorum has the composition, arabinose (26%), rhamnose (6%), galactose (57%) and glucuronic acid (11%). The highly branched polysaccharide bears a striking resemblance to the acidic polysaccharide exudate from Araucaria bidwillii in belonging to the galactan group and in carrying outer chains terminated by arabinofuranose, rhamnopyranose, galactopyranose and glucuronic acid residues. Both polysaccharides contain the sequence O-rhamnopyranosyl-(1→4)-glucopyranosyluronic acid-(1→6)-galactopyranose in some of the outer chains.     

Isolation and characterization of wheat peroxidase isoenzyme B1

Two pure peroxidase isoenzymes B1 and D4 were isolated from the upper parts of 10-day-old wheat seedlings by means of gel and ion-exchange chromatography. Their MWs were 85000 and 24000 respectively. B1 was unstable and under various conditions it was converted to another isoenzyme, electrophoretically identical with D4. B1 contains about 40% of neutral sugars: 17.2% arabinose, 15.3% galactose, 5% glucose and traces of mannose. D4 is free of neutral sugars. None of the isoenzymes contained amino sugars. B1 oxidizes ferulic and p-coumaric acids. This oxidation has two pH optima of 4.4 and 5.4–5.6 and is inhibited by high concentrations of substrates, cyanide and azide. B1 oxidizes IAA in the presence of phenolic cofactor and Mn²⁺ ions. IAA oxidation has two pH optima of 4.5 and 5.6 and is inhibited by high substrate concentration, cyanide and azide, and by a number of indole derivatives. The main products of IAA oxidation are 3-methyleneoxindole and indole-3-methanol. o- and p- diphenols induce a lag period prior to IAA oxidation. Ferulic acid is oxidized during this lag period, probably to a dimer. B1 is able to produce H₂O₂ from oxygen. Mn²⁺ ions, a phenolic cofactor and an electron donor (IAA or NADH) are needed. B1 oxidizes α-keto-γ- methylmercaptobutyric acid to ethylene. D4 has a low peroxidatic activity and is inactive as an IAA oxidase. Thus B1 is probably an active cell wall-bound peroxidase isoenzyme, whereas D4 is its decomposition product.